• Journal of the Korean Magnetics Society
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• v.23 no.5
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• pp.173-177
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• 2013

This work describes the experimental investigations on sloshing characteristics of water and ferrofluid as working fluids in the spherical container with the horizontal oscillation motion and compared the results obtained by two working fluids. In order to Investigate the sloshing characteristics of the sphere container with the horizontal oscillation, experiments are performed with the magnetic intensities from 0 mT to 50 mT and horizontal oscillation motions from 5 mm to 15 mm. As results, Ferrofluid without magnetic field in the sphere container showed a similar liquid surface movement with water. The resonance point of the ferrofluid in the sphere container happened at higher value than that of the theoretical resonance frequency with the rise of the magnetic field. In addition, the sloshing characteristics of the ferrofluid in the sphere container can be controlled with the resonance frequency with the magnetic intensity and the liquid surface displacement could be also controlled.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.543-547
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• 2002

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.75-80
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• 2002

• 유체기계공업학회:학술대회논문집
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• 1997.02a
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• pp.166-172
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• 1997

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.1
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• pp.48-54
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• 2002

This paper is described the indirect induction heated boiler and induction heated hot air producer using the voltage-fed series resonant high-frequency inverter which can operate in the frequency range from 20 kHz to 50 kHz. A specially designed induction heater is composed of laminated stainless plates, which have many tiny holes and are interconnected by spot welding. This heater is inserted into the ceramic type vessel with external working coil. This working coil is connected to the inverter and turbulence fluid through this induction heater to moving fluid generates in the vessel. The operating performances of this unique appliance in next generation and its effectiveness are evaluated and discussed from a practical point of view.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.3
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• pp.170-179
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• 2019

In this study, the wave responses in a 'Y'shape water channel resonator for amplifying wave energy of a low density has been investigated. A water channel resonator is composed of the long channel and wave guider installed at the entrance. If the period of the incident waves coincides with the natural period of the fluid in a water channel resonator, resonance occurs and the internal fluid amplifies highly to a standing wave form. In order to analyze the wave response in a water channel resonator, we used the matched asymptotic expansion method and boundary element method. The both results were in good agreement with the results of the model test carried out in the two-dimensional wave tank of Jeju National University. Wave guider has an optimum length and installation angle according to the period of the incident wave, and especially effective in enhancing the amplification factor in a period range deviated from the resonance period. It is expected that the wave energy can be effectively extracted by placing the point absorber wave energy converter at the position of anti-node where the maximum wave height is formed by the internal fluid resonance.

• Journal of the Korean Magnetics Society
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• v.22 no.5
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• pp.183-187
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• 2012

In this paper, fluid movement of magnetic fluid which has free surface is investigated in a container subjected to a horizontal oscillation. Here, the vertical magnetic field is applied from the bottom of this container. The experiment is performed on the magnetic fluid in a rectangular and a cylindrical container and the effects of magnetic force exerted on the magnetic fluid are investigated on the resonance frequency and liquid surface displacement. The increase of magnetic field affects on the maximum resonance point and the liquid surface displacement. In result, it changes the amplitude of the surface wave and the period of sloshing fluid movement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.506-513
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• 2015

In this paper, we proposed a novel ethanol concentration sensor using microfluidic metamaterial absorber. The metamaterial absorber comprises a split-ring-cross resonator(SRCR) and a microfluidic channel. The SRCR can generate LC resonance that is very sensitive to changes in the effective dielectric constant around the capacitive gap. In addition, microfluidic channels can change the effective dielectric constant of the dielectric substrate by using an infinitesimal quantity of a liquid on the order of microliters. The proposed absorber can detect the electrical properties of different concentration of ethanol. The performance of the proposed absorber is demonstrated using the absorption measurements of a fabricated prototype sample with waveguides. In addition, the simulated results and measurement results show good agreement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.309-313
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• 2009

A micromechanical resonance sensor detects the resonance frequency shift due to mass or adsorption induced surface stress change during molecular adsorption or interaction on its surface. The resonance sensor is surrounded by gas or liquid solution during operation. To study the resonance shift phenomena depending on its surrounding environment, fluid-structure interaction of the resonance sensor has been analyzed for the different fluid environment and boundary conditions using finite element analysis.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.49-52
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• 2007

본 논문에서는 FEM (Finite Element Method)을 이용한 압전세라믹의 특성해석을 통하여 잉크젯 프린트헤드를 설계, 제작하였다. 압전세라믹의 물질 특성과 잉크유체 특성을 고려한 굽힘 모드방식의 구동원리와 이론정립을 하였다. 압전방정식은 압전구조에 의한 공진주파수로 압전 파라미터를 구할 수 있고, 실험을 통하여 이러한 측정값을 얻을 수 있었다. 제작된 압전세라믹 프린트헤드의 잉크드롭 실험결과 통하여 이에 대한 특성을 알 수 있었다. 이때 잉크유체의 음파와 압전 공진주파수 범위 내에서 압전세라믹 응력(변형)의 이득을 발생할 수 있음을 제작한 128노즐의 압전세라믹 잉크젯 프린트헤드로부터 알 수 있었다.